1. Field of the Invention
The present invention relates to an air intake system of an engine, especially to a unitization of the air intake system mounted on a vehicle.
2. Description of the Related Art Including Information Disclosed under 37 CFR 1.97 and 1.98
In a conventional air intake system, a throttle and an air flowmeter or an air cleaner case are connected to each other by a duct in an engine room (compartment) and the air cleaner case is connected to a vehicle body. The air intake system requires a large space for arranging the air intake system between the air cleaner case and the engine, and a long connection line by the duct because the air cleaner case is mounted on the body. Therefore a large amount of man-hours is needed for designing an arrangement of members in an engine room. It is necessary to design the members so as to effectively fit to space and form of the engine room for every different kind of the vehicles, and therefore standardization or modularization of each of the members is difficult.
In order to solve the above problem, JP-A8-334070 discloses an air intake system shown in FIG. 21. The air intake system is composed of an air cleaner case 110 comprising an air cleaner cap 112 and a dusty side case 11 provided in a vicinity of a cylinder head of an engine 100, a surge tank 130 comprising a surge tank cap 132 and a lower case 131 provided on opposite side to the air cleaner case 110 at a different side of the engine, a throttle 140 connecting to the air cleaner case 110, and an intake manifold 120 molded in a form of a tube by an upper wall side 121 and a lower wall side 122 extending from the surge tank 130 to an intake port of the engine 100 through an under side of the air cleaner case 110. As shown in FIG. 22, the dusty side case 111 of the air cleaner case 110, the upper wall side 121 of the intake manifold 120, and the surge tank 130 of the lower case 131 are monolithically molded by using a plastic resin to form a housing. The upper wall side 121 is used in combination with a bottom side of the dusty side case 111 and a bottom side of the lower case 131.
Then, the air cleaner case 110, the throttle 140, the surge tank 130 and the intake manifold 120 are assembled to be united whereby the intake system is prepared, respectively. The publication has suggested attaching the intake system to the engine 100 as a unit.
JP-A10-318056 discloses an intake system shown in FIG. 23. The intake system is provided with an air cleaner case 153 having an element 152 therein, a throttle 154 into which air passed through the air cleaner case 153 is introduced, and the intake manifold 155 for introducing the air passed through the throttle 134 to the side of the engine 100, and further provided with a bottom case 162 molded monolithically including the air cleaner case 153 and a part 156 of the intake manifold 155, an intermediate case 163 which is removable from the case bottom 162 and inside which the element 152 is stalled, and a case cover 161 which is removable from the intermediate case 163 and which covers the air cleaner case 153.
According to the disclosures of JP-A8-334070 and JP-A10-318056, the intake system including the air cleaner case to the intake manifold is integrated as a unit, and it is mounted onto the engine as the unit. Therefore, the intake system is totally provided in the vicinity of the engine whereby the space within the engine room can be reduced and design of the arrangement of the members within the engine room can be easily carried out.
However, since the air cleaner case and the throttle are arranged over the intake manifold connected to the engine, the height of the intake system is increased to reduce clearance between the intake system and a hood covering the engine room. As a result, in case a pedestrian is contacted with a hood to apply impact load onto the hood, deformation of the hood is disturbed by the intake system. Therefore a disturbance affects adversely an absorption or decrease of the impact energy by the deformation of the hood. In contrast, in case the hood is raised for ensuring sufficient crush stroke, visible range of a driver or running resistance is affected badly and freedom of a body design is restricted.
In view of the above-mentioned problems, an object of the invention is to provide the air intake system which is mounted over the engine such as a horizontally opposed engine or V-type engine and which can be compactly prepared and easily modularized.
A first invention to attain the above object is provided by an air intake system of an engine which introduces air passed through a cleaner case having a filter element therein into a manifold through a throttle, and distributes the air from the manifold to each of cylinders of the engine by an intake element. The manifold is mounted on the upper side of the engine through the intake element connected to both sides of the manifold opposite to each other, and the cleaner case is connected to the manifold. The intake element also has plural intake pipes which are provided side by side and vertically to both of the sides of the manifold opposite to each other and of which each end on an upstream side of the intake pipes is opened and each end on a downstream side of the intake pipes connects to each of intake ports of the engine. In addition, the throttle is provided in the manifold such that a center axis of the throttle is substantially horizontal and centered in the vertical direction between the ends on the upstream side of the intake pipes provided vertically and extends to a center between the ends on the upstream side opposite to each other provided on both sides of the manifold.
According to the above invention, the throttle is provided such that a center axis of the throttle is provided substantially horizontal and in a center in a vertical direction between the ends on the upstream side of the intake pipes vertically provided and extended to a center between the ends on the upstream side opposite to each other provided on both sides of the manifold. Therefore, an occurrence of turbulent flow of air in the manifold is depressed, and the air is fed evenly to each of the intake pipes, and further the air is introduced horizontally into the manifold, whereby the height of the manifold can be reduced, and simultaneously the height of the cleaner case can be effectively reduced. Moreover, the connection of the manifold to the cleaner case requires no duct to become compact of an intake system.
Hence, in case the intake system of the present invention is mounted in the engine room, clearance between the hood and the intake system can be easily ensured. Therefore, even if the pedestrian applies impact load onto the hood from the upper side, sufficient crush stroke can be ensured and the impact energy can be sufficiently absorbed or reduced by the deformation of the hood with safety to pedestrian being improved. On the other hand, the hood can be lowered without affecting the intake system, i.e., slant nose can be adopt, whereby the visibility of the driver and the reduction of the running resistance can be expected and freedom of the design of the body is extended.
The manifold and the cleaner case can be mounted on the engine through the intake element as a sub-assembly unit. Therefore the production can be efficiently conducted, and the intake system is formed compactly, whereby it is easily mounted on other kinds of vehicles having the restricted form or effectively-spaced engine and the modularity is easily carried out.
A second invention to attain the above object is provided by an intake system of an engine which introduces air passed through a cleaner case having a filter element therein into a manifold through a main port and a throttle, and distributes the air from the manifold to each of cylinders of the engine by an intake element. The manifold is mounted on the upper side of the engine through the intake element connected to the manifold, and the cleaner case is connected to the manifold. The throttle is also connected to the manifold such that the center axis of the throttle is provided substantially horizontal and simultaneously an intake route of linking the throttle including the main port to the filter element is substantially linearly provided on the center axis of the throttle.
According to the above invention, the air is introduced horizontally into the manifold whereby the height of the manifold can be reduced, and further since the main port and the filter element are substantially arranged linearly on the extension of the center axis of the throttle extended substantially horizontally, resistance to intake in a route from the air cleaner to the throttle through the main port can be reduced and simultaneously the height of the cleaner case can be effectively reduced. Moreover, the connection of the manifold to the cleaner case requires no duct to make a compact intake system.
Hence, in case the intake system of the present invention is installed in the engine room, the clearance between the hood and the intake system can be sufficiently ensured. Therefore, even if the pedestrian applies impact load onto the hood from the upper side, the sufficient crush stroke can be ensured whereby the impact energy can be sufficiently absorbed or reduced by the deformation of the hood with safety to pedestrian being improved. On the other hand, the hood can be lowered, in this case the so-called slant nose can be adopt, whereby visibility of the driver and reduction of running resistance can be expected and the freedom of the body design is extended.
The manifold and the cleaner case can be mounted on the engine through the intake element as the sub-assembly unit. Therefore the production or the installation can be efficiently conducted, and the intake system is formed compactly, whereby it is easily mounted on other kinds of the vehicles provided with the engine room having the restricted form or the effective-space and the modularity is easily carried out.
A third invention to attain the above object is provided by an air intake system of an engine which introduces air passed through a cleaner case having a filter element therein into a manifold through a throttle, and distributes the air from the manifold to each of cylinders of the engine by an intake element,
wherein the manifold is mounted on the upper side of the engine through the intake element connected to the manifold,
the cleaner case, which in the form of a hollow, is connected to the manifold, and obtained by monolithically forming both of the filter cleaner case having the filter element divided by a partition therein and a blowby room constituting a blowby gas reflux system.
According to the above invention, the inside of the cleaner case in the form of the hollow is divided by the partition into the air cleaner case and a blowby room, and therefore both of the air cleaner case and the blowby room can be monolithically formed and compactified. Further the connection of the manifold to the cleaner case also requires no duct to make the intake system compact.
Hence, in case the intake system of the invention is installed in the engine room, the clearance between the hood and the intake system can be sufficiently ensured. Therefore, even if the pedestrian applies impact load onto the hood from the upper side, the sufficient crush stroke can be ensured and the impact energy can be sufficiently-absorbed or reduced by the deformation of the hood with safety to pedestrian being improved. On the other hand, the hood can be lowered, in this case the so-called slant nose can be adopt, whereby visibility of the driver and reduction of running resistance can be expected and the freedom of the body design is extended.
Further, the manifold and the cleaner case can be mounted on the engine as the sub-assembly unit. Therefore the production can be efficiently conducted, and the intake system is formed compactly, whereby it is easily mounted on other kinds of vehicles provided with the engine room having the restricted form or effectively-spaced vehicle and the modularity is easily carried out.
The embodiments of the first, second and third inventions are as follows:
In the first invention, it is preferred that the cleaner case has the filter cleaner case having the filter element therein and the main port leading the air from the air cleaner case to the throttle, and the intake air route of linking the throttle including the main port to the filter element is substantially arranged linearly on an extension of the center axis of the throttle.
According to the above embodiment, the intake route of linking the throttle to the filter element is substantially arranged linearly on the extension of the center axis of the throttle, whereby resistance to intake of the route from the air cleaner to the throttle through the main port can be reduced and the height of the air cleaner case can be effectively lowered.
In the third invention, it is preferred that the cleaner case is connected to the manifold at substantially the same height as each other.
According to the above embodiment, the clearance between the hood and the intake system is more easily ensured by connecting the cleaner case and the manifold at substantially the same height.
In the first, second and third inventions, preferred is the following embodiment: the cleaner case has;
the cleaner case body molded monolithically from a resin, which has the lower portion of air cleaner case opening the upper side and having the filter element therein and the lower portion of the blowby room opening its upper side which are divided into by a partition,
the case cover molded monolithically from a resin, which has the upper portions of the air cleaner case and the blowby room which cover the upside of the lower portions of the air cleaner case and the blowby room,
the cleaner case is a hollow cleaner case and includes the lower and upper portions of the air cleaner case into which the filter element is installed and which is formed by combining the cleaner case body to the case cover, and
the blowby room is formed from the lower and upper portions of the blowby room, which constitute a blowby gas reflux system.
According to the above embodiment, the air cleaner case into which the filter element is incorporated and the compacted cleaner case in the vicinity of the blowby case are easily produced by the cleaner case body and the case cover which are formed from the resin having excellent molding properties and capable of providing a light molded product. Therefore the cost for the production can be reduced. Moreover, the cleaner case, which may contact the hood by the deformation when the pedestrian contacts the hood to apply impact load onto the hood, is formed from a relatively flexible resin, whereby safety to pedestrian is improved.
In the first, second and third inventions, preferred is the following embodiment: the cleaner case body is molded monolithically such that the main port, which leads the air from the inside of the air cleaner case to the throttle through the lower portions of the air cleaner and the blowby room, is further incorporated into the cleaner case body.
According to the above embodiment, the blowby room is formed between the air cleaner case and the manifold by the provision of the main port of passing through the air cleaner to protrude from the air cleaner case, whereby a compact cleaner case having collectively three functions of the air cleaner case, the manifold and the main port can be formed.
In the third invention, it is preferred that the blowby room comprises a first blowby room separating foreign matters from a fresh air fed from the air cleaner to a crank case of the engine and a second blowby room separating the foreign matters from the blowby gas recycling between the crank case of the engine and the manifold, the first and second blowby rooms being divided by a partition wall.
According to the above embodiment, the blowby room is divided by a partition wall whereby the first and second blowby rooms can be formed, a first blowby room separating the foreign matters in the fresh air to be fed from the air cleaner to the crank case of engine and the second blowby room separating the foreign matters of the blowby gas recycling between the crank case of engine and the manifold.
In the first, second and third inventions, preferred is the following embodiment: a fixing member for supporting an air flowmeter is provided on the cleaner case body or the case cover.
According to the above embodiment, the air flowmeter can be easily mounted on the cleaner case by providing a fixing member for supporting the air flowmeter on the cleaner case body or the case cover.
In the first invention, it is preferred that the intake element is divided into a pair of intake elements each of which is connected to each of the sides of the manifold.
According to the above embodiment, since the intake element is connected to each of the sides of the manifold, it is possible to connect another different intake element to the manifold depending upon a different specification including engine performance. In other words, the manifold can be used in common in various engines. Further, the intake element is dividedly structured to enable the intake element to compact, whereby a mold for molding the intake element can be compacted with reduction of the production cost. Furthermore each of the intake elements is prepared in the same structure and therefore the kinds of constituent members can be reduced with enhancement of the productivity.
In the first invention, it is preferred that an inter cooler is connected to the manifold at substantially the same height as the manifold instead of the cleaner case.
According to the above embodiment, the inter cooler is connected to the manifold instead of the cleaner case and therefore the manifold and the intake element can be also used in a turbo engine.
A fourth invention to attain the above object is further provided by an intake system of an engine which introduces air passed through a cleaner case having a filter element therein into a manifold through a throttle, and distributes the air from the manifold to each of cylinders of the engine by an intake element,
wherein the manifold and the intake element, which are separately formed in advance, are bonded to each other by monolithically connecting an installation opening which opens at the manifold to an end on an upstream side of the manifold, and an end on a downstream side of the intake element is mounted on an upper side of the engine.
According to the above invention, the manifold and the intake element are separately formed in advance, and then are monolithically connected to each other. Therefore, the manifold and the intake element can be designed without considering influence therebetween, that is, the freedom of the design of the manifold and the intake element is ensured to permit compactification of the manifold and further compactification of the intake system.
Consequently, in case the intake system of the present invention is installed in the engine room, the clearance between the hood and the intake system can be easily ensured. Even if a pedestrian applies impact load onto the hood from the upper side, the sufficient crush stroke can be ensured whereby the impact energy can be sufficiently absorbed or reduced by the deformation of the hood with safety to pedestrian being improved.
Further, with compared to the monolithic molding of the manifold and the intake element, the intake system of the invention permits simplification and compactification of the shape to facilitate the molding, and simultaneously to bring about miniaturization of the mold thereof and reduction of the production cost.
Furthermore, by substituting the intake element by another one depending upon variation of the engine specification, the intake system of the invention can be used in various engines, and therefore the manifold can be used in common, i.e., can be modularized.
In the fourth invention, it is preferred that the cleaner case is molded monolithically from the resin such that it is connected to the manifold at substantially the same height as each other.
According to the above embodiment, the cleaner case is arranged at substantially the same height as the manifold, and these are connected to each other, whereby no duct is needed and the intake system can be rendered compact. The cleaner case is monolithically molded from the resin having excellent molding properties and capable of providing a light molded product, whereby the cost of the production can be reduced. Moreover, the cleaner case, which may be brought in contact with the hood by the deformation when the pedestrian contacts the hood to apply impact load onto the hood, is formed from a relatively flexible resin, to improve safety to pedestrian.
Since the intake system further has a feature that it can be prepared in the compact form, it can be easily provided in other kinds of vehicle restricted in shape or effective space, and therefore the modularity is facilitated.
In the fourth invention, it is preferred that the manifold has a installation opening which opens at a side of the manifold,
ends on the upstream side of the intake element are monolithically connected to the has an installation opening,
and the intake element extends in a curve (in the form of bay) downward from said connected point, and the end on the downstream side of the intake element is mounted on the engine.
According to the above embodiment, the ends on the upstream side of the intake element are connected to the has a installation opening of the manifold and curvedly formed downwardly from said connected point, and the ends on the downstream side of the intake element are mounted on the engine. Hence, the space between the manifold and the engine can be reduced and an effective length of the intake element can be ensured.
In the fourth invention, it is preferred that the manifold has installation openings which open at each of both sides of the manifold opposite to each other,
the ends on the upstream side of each of the intake elements are monolithically connected to each of the installation openings,
and each of the intake elements extends in a curve in the form of bay downward from each of said connected points and a pair of ends on the downstream side of the intake element are mounted on the engine.
According to the above embodiment, in addition to the previous embodiment, each of the intake elements is connected to both sides of the manifold opposite to each other, whereby the manifold can be more stably supported on the engine with the intake being evenly distributing into each of the cylinders.
In the fourth invention, it is preferred that the installation openings which open at both sides of the manifold have the same form as each other, and the openings of a pair of intake elements have the same form as each other.
According to the above embodiment, the installation openings of the intake elements which open at both sides of the manifold have the same form as each other, which results in reduction of the constituent members, whereby the productivity is enhanced and the production cost is expected to decrease.
In the fourth invention, it is preferred that the intake element is provided with intake pipes and installation flanges on the upstream side and the downstream side for connecting ends on the upstream and downstream sides of the intake tube to each of the installation openings of the manifold and an intake port of the engine,
the installation flange on the upstream side has a installation flange body in contact with the side surface of the manifold along a periphery of the installation opening and a inserting part, which is protruded on the installation flange, for inserting in the installation opening, and
the periphery of the installation opening and the installation flange body are bonded to each other by ultra sonic welding.
According to the above embodiment, the relative positioning of the manifold and the intake element are easily determined by inserting the inserting part on the installation flange at the upstream into the installation opening to bring the installation flange body in contact with the manifold, and the periphery of installation opening and the installation flange body are bonded to each other by ultra sonic welding. Hence, even if the manifold and the intake element are made up of different materials from each other, they can be easily and firmly bonded to each other and the side of the manifold is reinforced, whereby rigidity required in the manifold can be reduced to bring about extend of the design freedom.
In the fourth invention, it is preferred that the manifold is monolithically molded from the resin, and the intake element is monolithically cast (founded) from a metal or the resin, or monolithically molded from the resin.
According to the above embodiment, the manifold not requiring high heat resistance can be monolithically molded from the resin having excellent molding properties, and the miniaturization of the intake element brings about that of production mold whereby the reduction of the production cost and weight can be obtained. Further, the manifold is easily deformed by application of impact load. Therefore, even if a pedestrian applies impact load onto the hood from the upper side, the impact energy is absorbed or reduced by deformation of the hood with safety to pedestrian being improved.
In the fourth invention, it is preferred that wherein the throttle is provided in the manifold such that the center axis of the throttle is substantially horizontal, and
the cleaner case has the air cleaner case having the filter element therein and a main port leading the fresh air from the air cleaner case to the throttle, and an intake route linking the throttle, including the main port, to the filter element is arranged linearly on an extension line of the center axis of the throttle.
According to the above embodiment, the intake route of linking the throttle to the filter element is substantially arranged linearly on an extension of the center axis of the throttle, whereby resistance to intake of the route from the air cleaner to the throttle through the main port can be reduced with a height of the air cleaner case being effectively lowered.
In the fourth invention, it is preferred that an inter cooler is connected to the manifold at substantially the same height as the manifold, instead of the cleaner case.
According to the above embodiment, by connecting the inter cooler instead of the cleaner case to the manifold, the manifold and the intake element can be also used in a turbo engine.